JPS6366467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small, simple, and high-speed color document reading device used in facsimiles and the like.

A conventional device of this type was constructed as described below.

FIG. 1 is a schematic diagram of the configuration of a conventional color document reading device, in which 1 is a color document, 21, 22, and 23 are fluorescent lamps that emit red, green, and blue, respectively, 3 is a CCD line sensor, 4 is a lens, and 5 is a document feeding roller.

In order to operate this, the red, green, and blue fluorescent lights 21, 22, and 23 are turned on alternately every fixed period of main scanning, and each time the fluorescent lights of each color are turned on, the lens 4 is turned on. Therefore, the optical image of the color original 1 formed on the CCD line sensor 3 is photoelectrically converted to read the color information of the color original 1.

However, since such a device uses fluorescent lamps 21, 22, and 23 as light sources, the device inevitably becomes larger. In addition, fluorescent lights 21, 2
2 and 23 have an afterglow time of several milliseconds or more even when the power is turned off, and in order to avoid color information crosstalk, the next fluorescent lamp is turned on while this afterglow time exists. Can not do it. This has resulted in the drawback that the operating speed of the device is limited.

FIG. 2 is a schematic diagram of the configuration of another conventional color document reading device, in which 1 and 5 are the same as in FIG.
4 and 25 are LED arrays that emit red and green light, respectively; 41 is a focusing fiber lens array; and 31 is a thin film line sensor in which a row of photoelectric conversion elements is arranged in the same dimension as the original width.

To make this work, similar to the example in Figure 1,
Red and green LED array 2 every fixed period of main scanning
4 and 25 are turned on in turn, and each time each color LED array is turned on, the optical image of the color original 1 formed on the thin film line sensor 31 by the focusing fiber lens array 41 is photoelectrically converted. , reads the color information of the color original 1. In this example
Since it uses an LED as a light source, it is smaller than the example shown in Figure 1, and in the case of Figure 1, which uses a CCD line sensor 3, for example, considering a device that reads the short side of an A4 sheet, The width of the original is approximately 210mm, and the size of the photoelectric conversion element array of a commercially available 1728-pixel CCD is approximately 30mm, so a 1/7 reduction optical system is required.
The optical path length to CCD line sensor 3 is 300 to 400
It will be about mm. On the other hand, thin film line sensor 3
In the case of FIG. 2, which uses a converging fiber lens array 41 and a focusing fiber lens array 41, it is a one-to-one imaging system, so the optical path length is extremely small, about 30 to 40 mm. Furthermore, the response time of the light emission to power on and off is several seconds.
The operation speed is fast as it is as fast as 100msec.

However, the quantum efficiency of LEDs decreases rapidly as the wavelength of light emitted becomes shorter, so only red and green LEDs can provide sufficient light emission intensity. Therefore, a device using only such an LED as an illumination light source has the disadvantage that only insufficient color information can be obtained. In addition, LED arrays 24, 25
Since it is a red or green monochromatic LED array, one must be placed on the other side of the focusing fiber lens array 41, which has the disadvantage that there is no room for implementing other illumination sources, such as a blue light source. .

In order to solve these drawbacks, this invention utilizes a thin film line sensor in which a photoelectric conversion element array is arranged in the same dimension as the document width, a focusing fiber lens array, a red and green two-color LED array, and a blue fluorescent panel. This constitutes a color original reading device. Hereinafter, this invention will be explained in detail with reference to the drawings.

FIG. 3 is a schematic cross-sectional view showing the overall configuration of a color document reading device according to an embodiment of the present invention, in which numerals 1 and 5 are the same color document and document feeding rollers as in FIG. 1, 31 is a thin film line sensor, 26 is 2 colors
LED array light source, 27 is a blue fluorescent panel, 41
61 is a focusing fiber lens array, 61 is a mounting jig, 62 is a pressing plate, and 63 is a protective cover. The details of each part will be further explained below with reference to FIGS. 4 to 10.

FIG. 4 is an enlarged sectional view of the main parts of the two-color LED array light source 26, in which 26G is a green LED chip;
R is a red LED chip, 261 is a reflective frame, 262 is a rod-shaped lens, 263 is a printed circuit board, and 264 is a heat sink.

FIG. 5 is an external perspective view of the two-color LED array light source 26, and 261 to 264 are the same as those in FIG. 4.

FIG. 6 is an enlarged perspective view of the two-color LED array light source 26, showing the printed circuit board 263 and the green LED chip 26.
The relationship between G and the array of red LED chips 26R is shown. As you can see from this diagram, 26 green LED chips
G and red LED chips 26R are arranged alternately.

FIG. 7 is an enlarged sectional view of the main parts of the blue fluorescent panel 27, in which 271 is a substrate, 272 is an anode electrode, 273 is a phosphor film, 274 is a filament,
275 is a transparent face glass, and 276 is a trichromatic filter.

FIG. 8 is an external perspective view of the blue fluorescent panel 27, and 271, 275, and 276 are the same as those in FIG. 7. Although not shown in FIGS. 3 and 7, 277 and 278 are an extraction electrode and an exhaust pipe for evacuation, respectively.

FIG. 9 is an enlarged sectional view of essential parts of the thin film line sensor 31, in which 311 is a transparent substrate, 312 is a photoconductive thin film, 313 and 314 are electrodes, and 311 is a transparent substrate, 312 is a photoconductive thin film, and 313 and 314 are electrodes.
A set of 2 to 314 constitutes one photoelectric conversion element.

FIG. 10 shows that the photoelectric conversion element is formed on a transparent substrate 31.
This figure shows how they are arranged in a straight line on 1. Although the electrodes 313 and 314 shown in FIG. 9 are omitted in FIG. 10, they are wired in a matrix.

Next, the operation of the embodiment shown in FIG. 3 will be explained. At each fixed period of main scanning, the green LED chip 26G, red LED chip 26R (Fig. 6), and blue fluorescent panel 27 of the two-color LED array light source 26 are turned on in turn, and each color light source is turned on. Each time, the optical image of the color original 1 formed on the thin film line sensor 31 by the converging fiber lens array 41 is photoelectrically converted by the thin film line sensor 31, and a color corresponding to the color of each color illumination light source is generated. get information.

Note that the blue fluorescent panel 27 emits light in the following manner. In FIG. 7, when a current is passed through the filament 274, thermoelectrons are emitted. At this time, when a predetermined positive voltage is applied to the anode electrode 272, the thermoelectrons are accelerated in vacuum and collide with the anode electrode 272. As a result, the phosphor film 273 on the anode electrode 272 is excited by collision and emits light. Fluorescent film 2 used here
Reference numeral 73 is, for example, a ZnO:Zn phosphor, and this phosphor responds to on/off of the anode voltage in a short time of 10 μsec or less.

As explained above, the present invention uses a thin film line sensor that can shorten the optical path length by arranging photoelectric conversion element arrays with the same dimensions as the document width, and a focusing slave fiber lens array, and uses a small light source that has a small size and a fast response speed. A two-color LED array that can emit red and green light with just one,
A small blue fluorescent panel with a fast response speed is used, and the two-color LED array and the blue fluorescent panel are arranged on both sides of a focusing fiber lens array to reduce the mounting volume.
Color originals can be read at high speed with a simple device. Furthermore, it is possible to obtain color separation information for three colors: green, blue, and red. Therefore, if the present invention is applied to a facsimile device, there is an advantage that a small, simple, and high-speed color facsimile device can be constructed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the configuration of a conventional color document reading device, FIG. 2 is a schematic diagram of the configuration of another conventional color document reading device, and FIG. 3 is a schematic cross-sectional view showing the overall configuration of an embodiment of the present invention. Figure 4 shows 2 shown in Figure 3.
FIG. 5 is an enlarged sectional view of the main parts of the color LED array light source; FIG. 5 is an external perspective view of the two-color LED array light source shown in FIG. 4; FIG. 6 is an enlarged perspective view of the two-color LED array light source shown in FIG. Figure 7 is an enlarged sectional view of the essential parts of the blue fluorescent panel shown in Figure 3, Figure 8 is an external perspective view of the blue fluorescent panel shown in Figure 7, and Figure 9 is an illustration of the thin film line sensor shown in Figure 3. FIG. 10 is an enlarged sectional view of the main part and a perspective view of the main part of the thin film line sensor shown in FIG. 9. In the figure, 1 is a color original, 5 is a document feed roller, 26 is a two-color LED array light source, and 26G is green.
LED chip, 26R is a red LED chip, 261 is a reflective frame, 262 is a rod-shaped lens, 263 is a printed circuit board, 264 is a heat sink, 27 is a blue fluorescent panel,
31 is a thin film line sensor, 41 is a focusing fiber lens array, 61 is a mounting jig, 62 is a pressing plate,
63 is a protective cover.

Claims (1)

[Claims] 1. A color document reading device that obtains color separation signals by switching and lighting three color illumination light sources of red, green, and blue, which includes a thin film line sensor in which a photoelectric conversion element array is arranged in the same dimension as the width of the document; A focusing fiber lens array, a two-color LED array in which red and green LED chips are arranged alternately in a straight line on a substrate, and a rod-shaped lens for condensing light is provided on the substrate, and a phosphor film on the substrate. and a blue fluorescent panel having a structure in which the fluorescent film and filament are covered with a box-shaped vacuum container, and the two-color LED array is arranged in a space on one side of the focusing fiber lens array, A color document reading device characterized in that the blue fluorescent panel is arranged in a space on the other side.